Mike Leigh’s 2008 film Happy-Go-Lucky, one of the most joyous of movies and one of the year’s very best, is a breezy two-hour character study that seems to have the vibrantly unfettered cheer of a coloring book as its foundational text. The character under review is Poppy, played by Sally Hawkins with a stirring and endearing earnestness. She is first shown alongside the opening credits coasting down London streets on a bicycle. As depicted in later scenes that show this high-spirited young woman bouncing on a trampoline, humorously springing in and out of the frame, she is a buoyant image of freedom and mobility. She is also the embodiment of singularity within the multitudes. Though she passes amongst the population of an active metropolis, and the city itself continues on around her, oblivious to her presence, she is a lovably welcome focal point for those who take time to know her. Fortunately, this includes the viewer of Happy-Go-Lucky.

Poppy stops at a bookstore where her vainly cordial chitchat fails to prompt a stoically snubbing employee to conversation. She browses the shelves and the book “The Road to Reality” catches her eye, but she is quick to dismiss the premise: “Don’t want to be going there,” she says (to herself, to the audience — it’s all the same). Indeed, throughout the film, Poppy does her best to avoid the trappings of a rigid, bland existence. But that is not to say she ignores reality altogether. Though her unconsciously chatty, complementary and compassionate character feels like a breath of fresh air swept in from some far-off fantasy world, her positivity only functions in contrast to that which surrounds her. In other words, if her unflappable optimism appears uncommon, and maybe a little annoying at times, it is only because the norm is so routinely pessimistic. Even when her bike is stolen, she reacts with an amiable gleam, muttering that she didn’t even get a chance to say goodbye.

Perhaps as expected given her engaging gregariousness, Poppy has a stalwart support system, a frequently giggly gaggle of friends and family including kindly inclusive coworkers and a tight-knit circle of boozy off-hours associates like her moody sister Suzy (Kate O’Flynn) and her saucy-sympathetic roommate Zoe (Alexis Zegerman). Another sister, married with a baby on the way, lives apart from this London clique and touts the superficially adult virtues of owning property and having a mortgage and pension. In the presentation of these women, Happy-Go-Lucky carries forth the consistent Leigh trope of subjective happiness and its many variations. What works for some may not work for all, and how Poppy’s particular pleasure interacts with others is given a marked juxtaposition in her association with the two main men of the film, the instantly smitten social worker, Tim (Samuel Roukin), and the just as quickly hostile driving instructor, Scott (Eddie Marsan).

While the relationship between Poppy and Tim is effortlessly pleasant, and it’s certainly an enviable romance for those of us who similarly fall for this bubbly odd-ball beauty, not everyone follows easily behind Poppy’s somewhat demanding demeanor. Hawkins admits her cheeky character has a “naughty twinkle,” and it is her relentless — maybe intentional, maybe instinctive — penchant for goading those who resist her impossibly chipper attitude that strikes diverging chords. Genuine though she may be, her banter and energy is both exhausting and infectious, and to Scott, it is downright exasperating. The weekly conflicts between Poppy and this auto-guru result in Happy-Go-Lucky’s more affecting moments of tension and conventionally antagonistic drama. In the combustible closeness of a Ford Focus (a “pressure cooker,” in Leigh’s words), the two butt heads over Poppy’s driving, her outlook on life, her silliness and her boots, deemed dangerously inappropriate by Scott (who also finds them uncomfortably attractive). As loving and open as Poppy may be, Scott is, by contrast, a bitter man tinged with racism, homophobia and blanket bigotry. But perhaps his biggest flaw, in terms of dynamic opposition to Poppy, is his strained seriousness.

Still, Scott is key to Poppy’s growth, and he is vital to Happy-Go-Lucky’s episodic scenario. Poppy works as an elementary school teacher — she is, not surprisingly, a natural with children — and one day sees two boys fighting on the playground. She stares on with initial bewilderment, disturbed and stunned by the aggression, but it is after witnessing Scott’s hostility, and noting its likely roots in a broken family and a rough childhood, that she springs into action (the bullying boy, as it turns out, is abused at home). Though Poppy “celebrates chaos” according to the virulent instructor, when he goes off on a tangent about the educational system emphasizing right brain versus left brain instruction, his disdain for lockstep conformity in favor of individuality proves the two are, in at least this one way, on the same page. Her time with Scott produces the film’s most disturbingly serious scene, but it is yet another component in the evolution of Poppy, another revelation of her character’s capacity for patient understanding and another instance of the life-changing trifles Leigh often exults.

This is the sort of elliptically progressive narrative and roundabout character development that Leigh does so well, and in Happy-Go-Lucky, such moments are key to Poppy’s maturation. This is no life-lessons-learned Hollywood drama, though. There is no grand turning point for Poppy, no great obstacle to overcome and emerge from as a bigger and better person. Instead, Hawkins and Leigh create a gradually, subtly, developing individual. The film, as Leigh himself has noted, is about learning. Poppy teaches, but through her interactions with others, particularly those new to her or different from her, she also learns and repeatedly discloses renewed layers of depth. Part of Leigh’s goal is to also challenge assumptions cast by she and others in the film, and to get viewers to likewise move beyond the surface.

Over the course of more than 20 years, Mike Leigh has amassed an outstanding filmography, from the manic Naked (1993), to the delightful Another Year (2010), to the evocative Mr. Turner (2014). His films, and none more so than Happy-Go-Lucky, are like his characters; they are self-contained entities, utterly unique and completely captivating. As it’s often reported, to varying degrees of accuracy, he generally begins his films sans screenplay, and from there engages with his cast in a lengthy, detailed process of collaborative rehearsal, improvisation and character development. Yet such a seemingly free-form approach can be deceiving. While Leigh may emphasize texture over plot (Happy-Go-Lucky is rather light in the whole plot department), his films are enormously thoughtful. With this movie, for example, he designed the feature to be motivated by Poppy’s vitality and her liberation, utilizing anamorphic widescreen for the first time to suggest the potential for movement, adding bursts of radiant, often discordant, color and implementing Gary Yershon’s “tuneful” score to punctuate the lively atmosphere of visual and tonal jubilation.

To return to the “character study” categorization, though, with so much of Happy-Go-Lucky’s attention on Poppy (she is a primary figure in all but roughly two scenes), it stands to reason that Sally Hawkins and her extraordinary screen creation surface as the film’s greatest gift. Hers is one of the finest female showcases in recent years, and she deservedly accrued a slew of awards for her excellent work (the film was equally lauded around the world, for Leigh’s direction and, oddly enough, his screenplay). Happy-Go-Lucky was Hawkins’s third film with Leigh, following her screen debut in All or Nothing (2002) and Vera Drake two years later. And while she has regularly given first-rate performances, there has been nothing quite like this. A capable comedienne, she emits adorable chortles, gasps and murmuring laments, and she’s a physical livewire of facial tics and flailing movements. Conversely, Leigh’s closer compositions of Poppy expose her profound introspection and a beautifully fleeting expressiveness.

It is clear that Leigh’s adoring camera is enamored by this young woman, both the character and the actress. How could it not be? With Poppy’s sincere interest in others, her bright, toothy smile and her boundless exuberance, she essentially demands attention. One worries slightly when her empathy takes a potentially risky turn (a nocturnal dialogue with a babbling vagabond), but her ability to diffuse the clash with Scott, and to tolerantly see beyond his prejudices, testifies to a resiliently considerate strength. “You can’t make everyone happy,” cautions Zoe. But Poppy will sure as hell try. That’s what she does. That’s who she is. And who wouldn’t want to spend some time with someone like that? We should all be so lucky.

Jeremy Carr (@jeremyrcarr) teaches film studies at Arizona State University and writes for the publications Vague Visages, Film International, Cineaste, Senses of Cinema, MUBI’s Notebook, Cinema Retro, Movie Mezzanine, Cut Print Film and Fandor’s Keyframe.